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Subpart H—Cement Production

§ 98.80 Definition of the source category.

The cement production source category consists of each kiln 

and each in-line kiln/raw mill at any portland cement 

manufacturing facility including alkali bypasses, and includes 

kilns and in-line kiln/raw mills that burn hazardous waste.

§ 98.81 Reporting threshold.

You must report GHG emissions under this subpart if your 

facility contains a cement production process and the facility 

meets the requirements of either §98.2(a)(1) or (2).

§ 98.82 GHGs to report.

You must report:

(a) CO2 process emissions from calcination in each kiln.

(b) CO2 combustion emissions from each kiln.

(c) CH4 and N2O combustion emissions from each kiln. You 

must calculate and report these emissions under subpart C of 

this part (General Stationary Fuel Combustion Sources) by 

following the requirements of subpart C.

(d) CO2, CH4, and N2O emissions from each stationary 

combustion unit other than kilns. You must report these 

emissions under subpart C of this part (General Stationary Fuel 

Combustion Sources) by following the requirements of subpart C.

§ 98.83 Calculating GHG emissions.
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You must calculate and report the annual process CO2

emissions from each kiln using the procedure in paragraphs (a) 

and (b) of this section.

(a) For each cement kiln that meets the conditions 

specified in §98.33(b)(4)(ii) or (b)(4)(iii), you must calculate 

and report under this subpart the combined process and 

combustion CO2 emissions by operating and maintaining a CEMS to 

measure CO2 emissions according to the Tier 4 Calculation 

Methodology specified in §98.33(a)(4) and all associated 

requirements for Tier 4 in subpart C of this part (General 

Stationary Fuel Combustion Sources).

(b) For each kiln that is not subject to the requirements 

in paragraph (a) of this section, calculate and report the 

process and combustion CO2 emissions from the kiln by using the 

procedure in either paragraph (c) or (d) of this section.

(c) Calculate and report under this subpart the combined 

process and combustion CO2 emissions by operating and maintaining 

a CEMS to measure CO2 emissions according to the Tier 4 

Calculation Methodology specified in §98.33(a)(4) and all 

associated requirements for Tier 4 in subpart C of this part 

(General Stationary Fuel Combustion Sources).

(d) Calculate and report process and combustion CO2

emissions separately using the procedures specified in 

paragraphs (d)(1) through (d)(4) of this section.
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(1) Calculate CO2 process emissions from all kilns at the 

facility using Equation H–1 of this section:

Where:

CO2 CMF = Annual process emissions of CO2 from cement 

manufacturing, metric tons.

CO2 Cli,m = Total annual emissions of CO2 from clinker 

production from kiln m, metric tons.

CO2 rm = Total annual emissions of CO2 from raw 

materials, metric tons.

k = Total number of kilns at a cement 

manufacturing facility.

(2) CO2 emissions from clinker production. Calculate CO2

emissions from each kiln using Equations H–2 through H–5 of this 

section.

Where:

Cli,j = Quantity of clinker produced in month j from 

kiln m, tons.

EFCli,j = Kiln specific clinker emission factor for 

month j for kiln m, metric tons CO2/metric ton clinker 

computed as specified in Equation H–3 of this section.

CKD,i = Cement kiln dust (CKD) not recycled to the 

kiln in quarter i from kiln m, tons.

EFCKD,i = Kiln specific CKD emission factor for quarter 

i from kiln m, metric tons CO2/metric ton CKD computed 

as specified in Equation H–4 of this section.

p = Number of months for clinker calculation, 12.

r = Number of quarters for CKD calculation, 4.
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2000/2205 = Conversion factor to convert tons to metric 

tons.

(i) Kiln-Specific Clinker Emission Factor. (A) Calculate 

the kiln-specific clinker emission factor using Equation H–3 of 

this section.

Where:

CliCaO = Monthly total CaO content of Clinker, wtfraction.

ClincCaO = Monthly non-calcined CaO content of Clinker, 

wt-fraction.

MRCaO = Molecular-weight Ratio of CO2/CaO = 0.785.

CliMgO = Monthly total MgO content of Clinker, wtfraction.

ClincMgO = Monthly non-calcined MgO content of Clinker, 

wt-fraction.

MRMgO = Molecular-weight Ratio of CO2/MgO = 1.092.

(B) Non-calcined CaO is CaO that remains in the clinker in 

the form of CaCO3and CaO in the clinker that entered the kiln as 

a non-carbonate species. Non-calcined MgO is MgO that remains in 

the clinker in the form of MgCO3and MgO in the clinker that 

entered the kiln as a non-carbonate species.

(ii) Kiln-Specific CKD Emission Factor. (A) Calculate the 

kiln-specific CKD emission factor for CKD not recycled to the 

kiln using Equation H–4 of this section.

Where:
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CKDCaO = Quarterly total CaO content of CKD not 

recycled to the kiln, wt-fraction.

CKDCaO = Quarterly non-calcined CaO content of CKD not 

recycled to the kiln, wt-fraction.

MRCaO = Molecular-weight Ratio of CO2/CaO = 0.785.

CKDMgO = Quarterly total MgO content of CKD not 

recycled to the kiln, wt-fraction.

CKDMgO = Quarterly non-calcined MgO content of CKD not 

recycled to the kiln, wt-fraction.

MRMgO = Molecular-weight Ratio of CO2/MgO = 1.092.

(B) Non-calcined CaO is CaO that remains in the CKD in the 

form of CaCO3and CaO in the CKD that entered the kiln as a noncarbonate species. Non-calcined MgO is MgO that remains in the 

CKD in the form of MgCO3and MgO in the CKD that entered the kiln 

as a non-carbonate species.

(3) CO2 emissions from raw materials. Calculate CO2

emissions from raw materials using Equation H–5 of this section:

Where:

rm = The amount of raw material i consumed 

annually, tons/yr (dry basis) or the amount of raw 

kiln feed consumed annually, tons/yr (dry basis).

CO2,rm = Annual CO2 emissions from raw materials.

TOCrm = Organic carbon content of raw material i or 

organic carbon content of combined raw kiln feed (dry 

basis), as determined in §98.84(c) or using a default 

factor of 0.2 percent of total raw material weight.

M = Number of raw materials or 1 if calculating 

emissions based on combined raw kiln feed.

44/12 = Ratio of molecular weights, CO2 to carbon.
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2000/2205 = Conversion factor to convert tons to metric 

tons.

(4) Calculate and report under subpart C of this part 

(General Stationary Fuel Combustion Sources) the combustion CO2

emissions from the kiln according to the applicable requirements 

in subpart C.

§ 98.84 Monitoring and QA/QC requirements.

(a) You must determine the weight fraction of total CaO and 

total MgO in CKD not recycled to the kiln from each kiln using 

ASTM C114–09, Standard Test Methods for Chemical Analysis of 

Hydraulic Cement (incoporated by reference, see §98.7). The 

monitoring must be conducted quarterly for each kiln from a CKD 

sample drawn either as CKD is exiting the kiln or from bulk CKD 

storage.

(b) You must determine the weight fraction of total CaO and 

total MgO in clinker from each kiln using ASTM C114–09 Standard 

Test Methods for Chemical Analysis of Hydraulic Cement 

(incorporated by reference, see §98.7). The monitoring must be 

conducted monthly for each kiln from a monthly clinker sample 

drawn from bulk clinker storage if storage is dedicated to the 

specific kiln, or from a monthly arithmetic average of daily 

clinker samples drawn from the clinker conveying systems exiting 

each kiln.

(c) The total organic carbon content (dry basis) of raw 

materials must be determined annually using ASTM C114–09 
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Standard Test Methods for Chemical Analysis of Hydraulic Cement 

(incorporated by reference, see §98.7) or a similar industry 

standard practice or method approved for total organic carbon 

determination in raw mineral materials. The analysis must be 

conducted either on sample material drawn from bulk raw kiln 

feed storage or on sample material drawn from bulk raw material 

storage for each category of raw material (i.e., limestone, 

sand, shale, iron oxide, and alumina). Facilities that opt to 

use the default total organic carbon factor provided in 

§98.83(d)(3), are not required to monitor for TOC.

(d) The quantity of clinker produced monthly by each kiln 

must be determined by direct weight measurement of clinker using 

the same plant techniques used for accounting purposes, such as 

reconciling weigh hopper or belt weigh feeder measurements 

against inventory measurements. As an alternative, facilities 

may also determine clinker production by direct measurement of 

raw kiln feed and application of a kiln-specific feed-to-clinker 

factor. Facilities that opt to use a feed-to-clinker factor must 

verify the accuracy of this factor on a monthly basis.

(e) The quantity of CKD not recycled to the kiln generated 

by each kiln must be determined quarterly using the same plant 

techniques used for accounting purposes, such as direct weight 

measurement using weigh hoppers, truck weigh scales, or belt 

weigh feeders.
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(f) The annual quantity of raw kiln feed or annual quantity 

of each category of raw materials consumed by the facility 

(e.g., limestone, sand, shale, iron oxide, and alumina) must be 

determined monthly by direct weight measurement using the same 

plant instruments used for accounting purposes, such as weigh 

hoppers, truck weigh scales, or belt weigh feeders.

(g) The monthly non-calcined CaO and MgO that remains in 

the clinker in the form of CaCO3or that enters the kiln as a noncarbonate species may be assumed to be a default value of 0.0 or 

may be determined monthly by careful chemical analysis of feed 

material and clinker material from each kiln using well 

documented analytical and calculational methods or the 

appropriate industry standard practice.

(h) The quarterly non-calcined CaO and MgO that remains in 

the CKD in the form of CaCO3or that enters the kiln as a noncarbonate species may be assumed to be a default value of 0.0 or 

may be determined quarterly by careful chemical analysis of feed 

material and CKD material from each kiln using well documented 

analytical and calculational methods or the appropriate industry 

standard practice.

§ 98.85 Procedures for estimating missing data.

A complete record of all measured parameters used in the 

GHG emissions calculations in §98.83 is required. Therefore, 

whenever a quality-assured value of a required parameter is 
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unavailable, a substitute data value for the missing parameter 

shall be used in the calculations. The owner or operator must 

document and keep records of the procedures used for all such 

estimates.

(a) If the CEMS approach is used to determine combined

process and combustion CO2 emissions, the missing data procedures 

in §98.35 apply.

(b) For CO2 process emissions from cement manufacturing 

facilities calculated according to §98.83(d), if data on the 

carbonate content (of clinker or CKD), noncalcined content (of 

clinker or CKD) or the annual organic carbon content of raw 

materials are missing, facilities must undertake a new analysis.

(c) For each missing value of monthly clinker production 

the substitute data value must be the best available estimate of 

the monthly clinker production based on information used for 

accounting purposes, or use the maximum tons per day capacity of 

the system and the number of days per month.

(d) For each missing value of monthly raw material 

consumption the substitute data value must be the best available 

estimate of the monthly raw material consumption based on 

information used for accounting purposes (such as purchase 

records), or use the maximum tons per day raw material 

throughput of the kiln and the number of days per month.

§ 98.86 Data reporting requirements.
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In addition to the information required by §98.3(c), each 

annual report must contain the information specified in 

paragraphs (a) and (b) of this section, as appropriate.

(a) If a CEMS is used to measure CO2 emissions, then you 

must report under this subpart the relevant information required 

by §98.36(e)(2)(vi) and the information listed in this 

paragraph(a):

(1) Monthly clinker production from each kiln at the 

facility.

(2) Annual facility cement production.

(3) Number of kilns and number of operating kilns.

(b) If a CEMS is not used to measure CO2 emissions, then you 

must report the information listed in this paragraph (b) for 

each kiln:

(1) Kiln identification number.

(2) Monthly clinker production from each kiln.

(3) Annual cement production at the facility.

(4) Number of kilns and number of operating kilns.

(5) Quarterly quantity of CKD not recycled to the kiln for 

each kiln at the facility.

(6) Monthly fraction of total CaO, total MgO, non-calcined 

CaO and non-calcined MgO in clinker for each kiln (as wtfractions).
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(7) Method used to determine non-calcined CaO and noncalcined MgO in clinker.

(8) Quarterly fraction of total CaO, total MgO, noncalcined CaO and non-calcined MgO in CKD not recycled to the 

kiln for each kiln (as wt-fractions).

(9) Method used to determine non-calcined CaO and noncalcined MgO in CKD.

(10) Monthly kiln-specific clinker CO2 emission factors for 

each kiln (metric tons CO2/metric ton clinker produced).

(11) Quarterly kiln-specific CKD CO2 emission factors for 

each kiln (metric tons CO2/metric ton CKD produced).

(12) Annual organic carbon content of raw kiln feed or 

annual organic carbon content of each raw material (wt-fraction, 

dry basis).

(13) Annual consumption of raw kiln feed or annual 

consumption of each raw material (dry basis).

(14) Number of times missing data procedures were used to 

determine the following information:

(i) Clinker production (number of months).

(ii) Carbonate contents of clinker (number of months).

(iii) Non-calcined content of clinker (number of months).

(iv) CKD not recycled to kiln (number of quarters).

(v) Non-calcined content of CKD (number of quarters)
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(vi) Organic carbon contents of raw materials (number of 

times).

(vii) Raw material consumption (number of months).

(15) Method used to determine the monthly clinker 

production from each kiln reported under (b)(2) of this section, 

including monthly kiln-specific clinker factors, if used.

§ 98.87 Records that must be retained.

(a) If a CEMS is used to measure CO2 emissions, then in 

addition to the records required by §98.3(g), you must retain 

under this subpart the records required for the Tier 4 

Calculation Methodology in §98.37.

(b) If a CEMS is not used to measure CO2 emissions, then in 

addition to the records required by §98.3(g), you must retain 

the records specified in this paragraph (b) for each portland 

cement manufacturing facility.

(1) Documentation of monthly calculated kiln-specific 

clinker CO2 emission factor.

(2) Documentation of quarterly calculated kiln-specific CKD 

CO2 emission factor.

(3) Measurements, records and calculations used to 

determine reported parameters.

§ 98.88 Definitions.

All terms used in this subpart have the same meaning given 

in the Clean Air Act and subpart A of this part